I've seen buildings where plywood was used as both wall sheathing and siding. T-111 is commonly used this way, for example.
Would it work to do the same thing on a roof?
I assume it wouldn't last decades, but maybe its lifespan is enough for certain short-lived projects.
I guess seams would be difficult, so it may be limited to a single sheet, so only very small roofs.
I also suspect that a steeper slope might be important, so it sheds debris and water easily. And maybe facing the sun, so it dries out faster.
With all that in mind, maybe we're only talking about a small woodshed or a place to store tools. Still, it seems like it could be useful within all these constraints.
Would marine plywood make a difference?